5G Waveform Techniques - nt.tuwien.ac.at

5G Waveform Techniques

Module 1: PHY Enhancements

Ljiljana [email protected]

November 15, 2016

Dependable Wireless Connectivity for the Society in Motion

Motivation for New 5G Waveforms

FBMC GFDM

UFMC

x-OFDM

Others

Spectral Efficiencyate

ncy

Co

e

Use

r Data

Rate

ility

Requirements

◮ <1ms latency

◮ Mobility

◮ 100 Mbps

◮ 10-100x more devices

◮ Energy efficiency

◮ Low cost

Investigating the most flexible technique!

Slide 2 / 16


Motivation for New 5G Waveforms

FBMC GFDM

UFMC

x-OFDM

Others

Spectral Efficiencyate

ncy

Co

e

Use

r Data

Rate

ility

Requirements

◮ <1ms latency

◮ Mobility

◮ 100 Mbps

◮ 10-100x more devices

◮ Energy efficiency

◮ Low cost

Investigating the most flexible technique!

Slide 2 / 16


Content

Filter Bank Multicarrier - FBMC

Universal Filtered Multicarrier - UFMC

Outlook

Slide 3 / 16


Content



Outlook

Slide 4 / 16


FBMC System Model and MMSE Equalizer

CHANNEL+ =

k-1

k

k+1

m-2m-1 m

2Lmax

m+1m+2

k-1

k

k+1

m-2m-1 m m+1m+2

EQUALIZATOR

Neq

2Lmax

k-1

k

k+1

m-2m-1 m m+1m+2

+ =

k-1

k

k+1

m-2m-1 m m+1m+2

Slide 5 / 16


Results - Impact of Different Lengths of Equalizer

0 5 10 15 20 25 30

SNR in dB

10-2

10-1

100

SE

R

Lmax=3,Neq=6

Lmax=3, Neq=15

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Results - Impact of Different Lengths of Impulse Response

0 5 10 15 20 25 30

SNR in dB

10-2

10-1

100

SE

R

Lmax=1,Neq=6

Lmax=3,Neq=6

Lmax=1,Neq=15

Lmax=3,Neq=15

Slide 7 / 16


Results - Impact of Different Velocities

SNR in dB

0 5 10 15 20 25 30

SE

R

10-2

10-1

100

MMSE equalizer with 200 km/h

MMSE equalizer with 400 km/h

one-tap equalzer with 200 km/h

one-tap equalzer with 400 km/h

Slide 8 / 16


Content



Outlook

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UFMC System Model1

◮ Preserved orthogonality between subcarriers

◮ Zero Postfix or Cyclic Prefix avoid ISI

◮ Similar complexity as in CP-OFDM

◮ Possible DFT spreading for PAPR reduction

1R1-165014“Subband-wise filtered OFDM for New Radio below 6GHz“ Nokia, Alcatel-Lucent Shangai Bell,

May 2016

Slide 10 / 16


Spectral advantages of UFMC

Subcarrier Index0 66 133 200 266 333 400 466 533 600 666 733

PS

D[d

B]

-70

-60

-50

-40

-30

-20

-10

0Bandwidth = 10 MHz

OFDM

UFMC

◮ Improved out-of-subband radiation◮ Better support of fragmented spectrum

Slide 11 / 16


PAPR Features

PAPR [dB]

0 2 4 6 8 10 12

CC

DF

10-4

10-3

10-2

10-1

100PAPR Comparison between UFMC and OFDM

UFMC without DFT spreading

OFDM

SC-FDMA

UFMC with DFT spreading

Slide 12 / 16


BER Performance for Different Transmission Modes

0 2 4 6 8 10 12 14 16 18

SNR[dB]

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

Bit E

rro

r R

atio

UFMC

SU SISO AWGN channel

SU SISO flat Rayleigh channel

Slide 13 / 16



0 2 4 6 8 10 12 14 16 18 20

SNR[dB]

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

Bit E

rro

r R

atio

UFMC



SU MISO 2x1 Alamouti

SU SIMO 1x2

Slide 13 / 16



0 2 4 6 8 10 12 14 16 18 20

SNR[dB]

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

Bit E

rro

r R

atio

UFMC




SU SIMO 1x2

SU MIMO 2x2

Slide 13 / 16



0 2 4 6 8 10 12 14 16 18 20

SNR[dB]

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

Bit E

rro

r R

atio

UFMC




SU SIMO 1x2

SU MIMO 2x2

MU MIMO, NrTx = 3, NrUsers = 3

Slide 13 / 16


Content



Outlook

Slide 14 / 16


Multi-user parameters optimization

Time

Fre

quency

Robust communcation(reduced spectral efficiency)

Low latency, high velocity(high efficiency if L >> K )

Large area(high efficiency if K >> L)

Required time-frequencyresources for one symbol

L ... Number of subcarriers per blockK ... Number of time-symbols per blockF ... Frequency-spacingT ... Time-spacing

F

T ∝1F

Slide 15 / 16


Outlook

◮ Presence of ICI even for AWGN channel!

◮ Smaller overhead than in OFDM ⇒ Time-frequency efficiency is better!

◮ Tradeoff between time-frequency efficiency and ICI ⇒ optimal length of the filterand number of guard subcarriers?

Thank you for your [email protected]

Slide 16 / 16


Outlook

◮ Presence of ICI even for AWGN channel!

◮ Smaller overhead than in OFDM ⇒ Time-frequency efficiency is better!

◮ Tradeoff between time-frequency efficiency and ICI ⇒ optimal length of the filterand number of guard subcarriers?

Thank you for your [email protected]

Slide 16 / 16


References I

Slide 1 / 1

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5G Waveform Techniques - nt.tuwien.ac.at